Phentermine is a sympathomimetic amine, similar in chemical make-up to amphetamine, and thus shares some of the same properties of amphetamines. It works to encourage
weight loss in two ways- firstly,
and most importantly, it affects neurotransmitters in the hypothalamus, which stimulate the central nervous system, this causing a reduction in appetite. Secondly, it raises heart rate, causing the basic metabolic rate to rise.